Chusetts



@atten tsts strnt @Hire HENRY W. eOOniuoH AND WILLIAM is. uAsON, Or BOSTON, MASSA Onusnrfrs.

` Letters Patent No. 64,305, dated April 30,1867.

IMPROVEMENT IN 4STEAM-ENGINE SLIDE-VALVES.

TO ALL WHOM IT MAY GONCERN:

Beit known that we, H. W.' GOODRICH and W. B. MASON, both of Boston, in the county of Suffolk, and State of Massachusetts, have invented an Improvement in the'Slide-.Valves of Stoa-m Engines; and We do hereby vdeclare that the following, taken in connection with the drawings which accompany and form part of this specification, is a description of our inventionsuiiicient to enable those skilledin the art to practise it.

` The object of this invention is to lessen the pressure which acts to force the faceof the valve upon its seat, by a transfer of the pressure to a carriage mounted on rolls in such a manner-that the valve is free at all-times to iind its seat or to adjust itself on its seat without reference to-or control 'by the relation ot'- the rolls to the track or surfaces upon which they run, the invention being intended for an'improvenlen't over that construction of slide-valvfsin whiclrthe valve itself rests and traverses upon rollers, theso having a definite and xed relation between their peripheries, the ltrack on which they roll, the valve-seat, and valve-face, which relation is very difficult of correct adjustment, and when once established is disturbed by the natural process of wearvwhich it is impossibleto avoid. In thedratvings- Figure 1 represents, in plan, Van embodiment of my invention; while Figure 2 is a section taken in the line e z seen in ig. 1.

a denotes, say for example, the main steam chest of a marine engine, which has a separate exhaust chest. is the valve-seat Within the chest, and e c denote the location of thc ports which convey the steam into the cylinder at either end. The valve dis represented as a plain slide Without exhaust passages, admitting'steam l and cutting'it oil' at its ends under movement imparted through the valve-rod e. On this valve is xed a short cylinder, Vz', truly bored to receive a closely tting piston, which may be packed like any pump or engine piston'. This piston is secured to a cross-bar, y, over it, and which rests on a frame, t, said frame being mounted on rollers or wheels 7c j'ournalled to the frame, and-which traverse on the valve-face or on any suitable bearing surface in the steam chest. It will now vbe seen that the only necessary connect-ion between th e valve and the frameis 'that which obtains by presence kof thepistonf in the cylinder 2, and that the valve and frame will both move together, whether the valve-rod is directly connected ,to the one or to the other. To lavoid, however, undue Wear and strain'ou the pistonf and cylinder z', we prefer to connect the valve cl and frame L by linksjj, through which the thrust and pull of the valve-rod can be exerted, the manner of connecting thc links being suc'h as willv freely permit vertical movements of the valve and frame with respect to cach other. It will now be obvious that upon whatever theory the pressure upon slide-valves generally is calculated, a large portion of the area of valve d is protected by piston'ffromfpressure, said piston itselt receiving a pressure which would Otherwise operate directly on the valve itselt`, and being xed tothe cross-beam y, said pressure is transferred to the frame/t, and thereby to the rollers'k, so that a large part of the pressure, which, but for the arrangement of the valve-cylinder i and the piston f, would have been exerted to create friction between the valve-face and the valve-seat, is exerted on the journals of the rollers c, thus saving unnecessary wear of the valve and its seu-t and espenditure ofpower, it taking far less power, under agiven load or pressure, to move the parts partly on rolls, than it would to move them entirely as sliding surfaces. By the described arrangement it is obvious that some of the arca of the valve is exposed to pressure; theamountiof this area may be varied by the designing engineer to suit the requirements of any ease, it being of advantage to have pressure enough on the valve to keep it firmly on the valve-seat. lVear of the valve-face, or ot' the valve-seat, or of the journals, or the peripherics of the trucks, or the rollers, will, it is obvious, have no other eti'ect than a slight relative change of position between the piston f and the back of the valve d. To relieve the cylinder from presence of water and steam which might collect therein, and so prevent relative movement between the cylinder and its piston, we propose to provide the cylinder with a pipe, located parallel with thevalvc-stcm and working through a stuffing-box in the steam chest. Through this pipe all the possible leakage will have an outlet, and tight packing ot the piston isrcndcred unnecessary.

We claim the combination of a slide-valve, a cylinder, apiston, and a carriage, arranged to operate together,

substantially as described.

HENRY W. GOODRICI-I,

WILLIAM B. MASON.

'Y Witnesses:

J. B. CROSBY, F. GOULD 

